Manifold Absolute Pressure Sensor (MAP)

GENERAL INFORMATION

Manifold Absolute Pressure Sensor (MAP)

1. MANIFOLD ABSOLUTE PRESSURE SENSOR

The MAP sensor converts the intake manifold pressure, which

depends on engine load and crankshaft speed, into an electrical

voltage..

With the throttle closed, the MAP sensor signal voltage is low, and with the throttle open it is high. As the throttle opens, the MAP signal changes in the

opposite direction compared to vacuum gauge readings. The MAP sensor is also used to measure atmospheric pressure with the engine

not running, which allows the ECM to adapt control algorithms to the specific

altitude above sea level, which allows the ECM to adapt control algorithms to the specific

altitude above sea level..

The ECM supplies the MAP sensor with a 5 V reference voltage. A change in intake manifold pressure causes a corresponding change in the electrical resistance of the

MAP sensor and the signal voltage.

The ECM determines the intake manifold pressure from the MAP signal voltage. At high pressure (low vacuum), the MAP sensor outputs a high voltage signal and the ECM increases fuel supply to the engine. At

low pressure (high vacuum), the MAP signal voltage decreases and the ECM reduces fuel supply. If the MAP sensor or wiring fails, the ECM sets a trouble code

for malfunction. The MAP sensor is also used to measure atmospheric pressure.

fault

33..

The MAP sensor is used to measure atmospheric pressure. With the ignition on and the engine not running, the ECM uses the MAP signal to correct air-fuel mixture control (compensation for changes in air density, which

depends on altitude above sea level). Altitude compensation helps reduce

the adverse effect of altitude above sea level on the level of harmful

substances in exhaust gases and on engine power. The atmospheric pressure value stored in the ECU memory is periodically updated during steady

driving of the vehicle and during full opening of the throttle valve.

Remove or disconnect:

PROCEDURE.

1. Vacuum hose..

2. Electrical connector..

3. Mounting screws..

4. Sensor..

Installation

PROCEDURE.

1. Sensor and mounting screws..

2. Electrical connector..

3. Vacuum hose.